Subjects with obstructive sleep apnea close their pharynx during inspiration when they sleep. Many investigators believe that this is due to laxity of the pharyngeal muscle. Most subjects with obstructive sleep apnea are obese. No one has previously studied whether fat can be deposited around the pharynx and narrow the pharyngeal airway. The purpose of this study is to determine whether airway closure and obstructive sleep apnea is due to narrowing of the pharyngeal airway.